Indications For Photodynamic Therapy Research Articles

Möglichkeiten und Grenzen der photodynamischen Therapie - Eine Übersicht

The spectrum of possible treatments for choroidal neovascularisation has been considerably increased with the introduction of photodynamic therapy. On the other hand the technical complexity and high cost associated with this new method require a pinpointed and dedicated application to achieve not only treatment benefits for the patients, but also not to exceed the available resources. This focussed application of the new treatment method can only be performed if the basics of diagnosis, indication, treatment and follow-up care are sufficiently known and used. The standard treatment protocol, the results of published clinical trials as well as many published clinical observations are presented and discussed. Photodynamic therapy with verteporfin can prevent massive loss of vision in many cases of subfoveal choroidal neovascularisation, but the treatment outcome depends on many factors, the most important being the underlying disease process. Hence, indication for photodynamic therapy should adhere to the published treatment guidelines. In the future, additional medications or alterations of the treatment protocol might improve treatment outcome.

Photodynamic therapy: where do we go from here?

Photodynamic therapy (PDT) involves the use of photosensitising agents that are selectively retained within tumour cells. The agents remain inactive until exposed to light of the proper wavelength. When activated by light, these compounds generate toxic oxygen radicals that result in tumour necrosis. In the current issue of the European Respiratory Journal , Moghissi et al. 1 have provided an exhaustive review of PDT and lung cancer. PDT appears to be a therapeutic technique, with a low toxicity profile and photosensitising agents, such as sodium porfimer, that have been approved by the Food and Drug Administration and European Agencies for the photodynamic treatment of early and late stage lung cancer. However, despite 2 decades of basic research and clinical experience, only a few centres have regular experience of PDT. Furthermore, several issues remain as yet unresolved, such as the best indications of PDT, the use of photosensitising agents other than sodium porfimer, or the comparison ofPDT and other endobronchial therapies, such as electrocautery, Neodymium-doped Yttrium …

Photodynamic therapy.

Photodynamic therapy (PDT) is a treatment modality that utilizes a photosensitizing drug activated by laser-generated light and is proving effective for oncologic and nononcologic applications in the gastrointestinal tract. This article provides an overview of the most frequently used photosensitizers and clinical PDT studies in the upper gastrointestinal tract. In the future, the best indications for PDT in the esophagus will not comprise the palliative treatment of obstructing tumors but precancerous lesions such as Barrett's esophagus with or without dysplasia and early cancer. PDT might establish itself as a minimally invasive treatment alternative compared with surgery for high-grade dysplasia or early mucosal cancer of the esophagus.

Intraoperative photodynamic therapy as an adjunct to surgery for recurrent rectal cancer

Locally recurrent rectal cancer is a difficult management problem for the surgical oncologist. Current therapies including radical surgery, radiation and chemotherapy have had little success in producing curative results for these patients. This study incorporated intraoperative photodynamic therapy (PDT) as an adjunct to radical surgery for the treatment of locally recurrent rectal cancer. Twenty-two patients were enrolled in a prospective feasibility study and injected with Photofrin (Quadra Logic Technologies, Vancouver, British Columbia, Canada) before surgery. Eight patients were found to be candidates and received PDT after surgical exploration and resection. Seven patients had rectal adenocarcinoma and one had squamous cell carcinoma of the anal canal. Based on the indication for PDT, three patient groups were evaluated: group A, resection of all gross disease with negative pathologic margins in four patients; group B, resection of gross disease with positive pathologic margins in two; and group C, residual bulky tumor in two patients. There was one perioperative death (12.5%), not related to PDT, and one major morbidity due to PDT (12.5%). Local recurrence occurred in six patients (two in group A, two in group B, two in group C). Mean overall survival was 15.4 months for group A, 6.5 months for group B, and 24.5 months for group C. The results of this study suggest that intraoperative PDT may be administered safely in patients undergoing resection of recurrent rectal cancer. However, its use in the present state of technology appears to be inadequate for control of disease, particularly if bulky tumor or residual microscopic disease is left behind.

Photodynamic Therapy for Esophageal cancer

In photodynamic therapy, a photosensitizing drug is injected and then activated by light in the red spectral region to produce reactive, highly toxic singlet oxygen, which causes cell tissue and damage. When the distinction between tumoral and normal tissue is difficult at endoscopy, photodynamic therapy is preferable to any other conservative method of destruction. The main indications comprise genital, head and neck, bronchial, bladder and gastrointestinal tumours, particularly esophageal cancer (including squamous cell cancer and glandular neoplasia). Esophageal tumours should be class T1 or T2, at most, and detected at endoscopy. Dysplasia which is flat, sessile and multicentric may also be an indication for photodynamic therapy. Advanced esophageal cancers are contraindicated for photodynamic therapy.

Use of photodynamic therapy in the treatment of oral and maxillofacial cancer and precancer: Report of 104 cases and preliminary observation on the mechanism

This paper describes the use of photodynamic therapy (PDT) in the treatment of 104 patients with premalignant or malignant disease of the oral cavity and maxillofacial regions. The tumours in 10 patients were submitted to detailed histological examination following resection 24 hours after PDT. In all patients the photosensitizer was haematoporphyrin derivative given in a dose of 2.5–5.0 mg/kg body weight, 48–72h before photoirradiation. Einghteen patients were treated with the helium-neon laser, with a power density of 120–200 mW/cm2 and a total energy dose of 200–500 J/cm2, but in this group a complete response was obtained in only 39% of patients. However, when the argon-pumped dye laser was used in the remaining cases, with a power density of 400–800 mW/cm2 and a total energy dose of 720–1440 J/cm2, the complete response rate rose to 72%. In the latter group, 15 patients were treated by fibre-optic implantation between the tumour and underlying normal tissues. From the histological study it would appear that PDT acts both on the blood vessels of the stroma and also at a cellular level, with some possible enhancement of immune function. Indications for PDT, based on this study, are defined.

肺がんの治療 とくにＰｈｏｔｏｄｙｎａｍｉｃ ｔｈｅｒａｐｙについて

Photodynamic therapy (PDT) using hematoporphyrin derivative (HpD) has been performed in 139 lesions of 115 lung cancer cases since 1980. The efficacy of and indication for PDT were discussed in this paper. Twenty-six cases were early stage lung cancer and 17 were stage I, 11 were stage II, 42 were stage III and 19 were stage IV, respectively. Complete remission was obtained in early stage cases with small lesion, however incomplete remissions or tumor recurrences were observed in large extent lesions.Opening of obstructed bronchus was obtained in the advanced lung cancer cases and improvements of performance status were obtained. It was also possible to increase the operability and to reduce the extent of resection area in the advanced cases.This modality has more possibilities in the treatment of malignant tumors in future.

光線力学的治療法における早期肺癌の治療適応

光線力学的治療法における早期肺癌の治療適応